I'm not going to quote everyone in my reply but one must start somewhere. I wasn't looking for the definitive answer just input from people with experience keeping them. Everything is relative of course, that's a given.
I'm leaning to Apistogramma Barlowi F1. They're mouth brooders. Looks really interesting. They are said to like white sand bottoms with a fast current. I have Eco-complete, can't get more opposite than that! But, I do have a pretty good current with 2 Eheim 2217's. Just sent an email to the seller about the substrate issue. I'd feel really bad if I got the fish, and then find out they're totally miserable. If that's the case then I might go with the Borelli - Red Cheek, wish I could find a picture of one.
The water in NYC is pretty soft, usually around 6.8 - 7. A friend of mine suggested the Apisto's since my water supply is well suited for them. Why fight it, just use what you have.
Keep' um coming folks, would love to hear about your experiences keeping apistos!!